It is commonly known to use stroke based input for text input or other graphic input in a wide variety of devices such as mobile phones, laptops with graphical user interfaces and Personal Digital Assistants (PDAs).
Stroke based input is commonly used for hand writing recognition (HWR) and the text input in such systems is effected by the user drawing the character using either a stylus (or a pen) or a finger on either a touch display or a dedicated touch input area. The stroke is then processed and a matching character is input to the system. Such input is sometimes referred to as pen input. One example of such a system can be found in the Sony Ericsson P900™.
In some systems, especially such systems utilizing touch displays, a graphic trace of the pen input is displayed. This helps the user see what he has input and helps the user to for example place diacritics in the correct position. The traces are either removed by an explicit command from the user or automatically after a timeout period(s) has lapsed. Requiring a special clear command adds one extra command for every character to be input which is tedious work, especially for long texts, and takes time. Using a time out may cause a trace to disappear before the user has had time to complete it or supplement it causing an erroneous recognition which requires a user to correct or repeatedly input such characters.
US Patent Publication No. US 2003038788 discloses a handheld device such as a personal digital assistant (PDA) or the like, a handwritten input user interface (HIUI), a method of interfacing handwritten text and a program product therefore. A lower portion of a touch enabled display is designated as a handwriting input area. Action icons are disposed at a right side of the handwriting user interface 102. Recognized text is displayed on the screen in a text display area located between a file management tool bar and the handwritten input area. A scroll bar is disposed at the right side of the display. As text is continuously entered each individual word may be recognized, and inserted into the end of the text stream. A word separator may demarcate or bracket individual words in a continuous input stream. A secondary list of potential recognition candidates may be available for display in a box and offered for substitution for or in lieu of the recognized word. Handwritten text may be continuously entered and displayed in the handwriting input area as digital ink, the input point staying approximately fixed with the ink display automatically scrolling. The input area behaves as a “treadmill” or “ticker tape” that is moving from right to left, thereby giving the illusion of a continuous writing space. The speed of the “treadmill” automatically adapts to writing speed. The device may include a communications function and, in particular the device may include an antenna for wireless communication. Individual function switches, buttons and other controls are disposed about the device.
As the input pen strokes are moved as on a ticker tape it can be confusing for a user to decide where to input the next character in that a specific starting point is not given and perhaps the user will become doubtful that there will be enough room if the user wants to input a large character or a long word. Also as the ticker tape moves the characters the user will have to adapt to this movement making the input less intuitive and some relearning is necessary which always requires a mental effort.